In recent years, the use of cellular communication systems having mobile devices which communicate with a hardwired network, such as a local area network (LAN) or a wide area network (WAN), has become widespread. Retail stores and warehouses, for example, may use cellular communication systems with mobile data terminals to track inventory and replenish stock. The transportation industry may use such systems at large outdoor storage facilities to keep an accurate account of incoming and outgoing shipments. In manufacturing facilities, such systems are useful for tracking parts, completed products and defects. Such systems are also utilized for cellular telephone communications to allow users with wireless telephones to roam across large geographic regions while retaining telephonic access. Paging networks also may utilize cellular communication systems which enable a user carrying a pocket sized pager to be paged anywhere within a geographic region.
A typical cellular communication system includes a number of fixed access points (also known as base stations) interconnected by a cable medium often referred to as a system backbone. Also included in many cellular communication systems are intermediate access points which are not directly connected to the system backbone but otherwise perform many of the same functions as the fixed access points. Intermediate access points, often referred to as wireless access points or base stations, increase the area within which access points connected to the system backbone can communicate with mobile devices. Unless otherwise indicated, the term "access point" will hereinafter refer to both access points hardwired to the system backbone and wireless access points.
Associated with each access point is a geographic cell. Such cell is a geographic area in which an access point has sufficient signal strength to transmit data to and receive data from a mobile device such as a data terminal or telephone with an acceptable error rate. Typically, access points will be positioned along the backbone such that the combined cell area coverage from each access point provides full coverage of a building or site.
Mobile devices such as telephones, pagers, personal digital assistants (PDAs), data terminals, etc. are designed to be carried throughout the system from cell to cell. Each mobile device is capable of communicating with the system backbone via wireless communications between the mobile device and an access point to which the mobile device is registered. As the mobile device roams from one cell to another, the mobile device will typically deregister with the access point of the previous cell and register with the access point associated with the new cell.
In order to provide sufficient cell area coverage, access points within the cellular communication system typically are distributed at separate physical locations throughout an entire building or set of buildings. For various reasons such as aesthetics, cell coverage, protection from the environment, etc., the access points typically are situated at locations hidden from view of the occupants and well removed from everyday traffic. Thus, it is not uncommon that access points are located above ceiling tiles or in other remote locations throughout the building or buildings.
At the same time, each access point must receive electrical power for operating the access point regardless of its particular physical location. In the past, it has been common practice to provide electrical power to each access point by installing a corresponding dedicated AC electrical power outlet (e.g., rated at 110 volts AC) in close physical proximity to each access point. Once installed, each access point is plugged into its dedicated AC outlet and receives operating power therefrom. Typically, the access point includes an AC-to-DC (AC/DC) converter which converts the power from the AC outlet to a suitable DC power level for operating the various electronics included within the access point.
Accordingly, the installation of a cellular communication system typically includes installation costs associated with adding an AC power line together with corresponding AC power outlets for each access point. Due to local electrical wiring codes, etc., each added outlet involves the cost of extra conduit and wiring needed to reach the location of the access point and the cost associated with hiring a licensed electrician to complete the work. Since the access points typically are located in difficult to reach locations (e.g., above ceiling tiles, etc.), installation of the AC wiring and conduit has been particularly time consuming for the electrician. As the number of access points required to serve a store or business is often large, the overall costs associated with supplying power to each access point has been high and adds significantly to the overall cost of installing a cellular communication system.
In view of the aforementioned shortcomings associated with the high installation costs for conventional cellular communication systems, there is a strong need in the art for a system which is less costly with respect to supplying power to access points within the system. In particular, there is a strong need in the art for a system which is both simple and inexpensive and does not require the high overhead associated with providing and installing dedicated AC power outlets.